Cold rolling mill with roll pass ring

ABSTRACT

A COLD ROLLING MILL OF THE STEP-BACK TYPE HAS A ROTATABLE SHAFT AND A ROLL PASS RING HEAT SHRUNK THEREON SUFFICIENTLY INTENSIVELY FOR THE SLIP-FREE CARRYING OUT OF HIGH-SPEED STEP-BACK ROLLING.

Mal'ch 9 FZ ZEUNERT ,5

' COLD RoLLtNs' MILL WITH ROLL PASS RING Original Filed Sept. 27, 1966\NVEN TOR ana ZEUNERT,

HIS ATTORNEY- United States Patent Int. Cl. Bzib 31/08 US. Cl. 72-238 1Claim ABSTRACT OF THE DISCLOSURE A cold rolling mill of the step-backtype has a rotatable shaft and a roll pass ring heat shrunk thereonsutficiently intensively for the slip-free carrying out of high-speedstep-back rolling.

This is a continuation of my application Ser. No. 582,288, filed Sept.27, 1966, now abandoned.

The invention relates to cold rolling mills, and relates moreparticularly to cold rolling mills of the step-back type for the coldrolling of tubes; still more particularly, the invention relates to coldrolling mills of this type utilizing roll pass rings.

It is known to use cold rolling mills of this type with two or moreworking passes in order to step up the production output of cold rolledtubes; this, however, has certain disadvantages, as it necessitates theuse of multiple equipment for clamping, turning and feeding the rolledstock, and therefore involves considerable expenditure and costs, apartfrom the fact that it requires the coordina tion of the moving actions.In order to avoid these disadvantages, cold rolling mills of thestep-back type have been proposed and used that had only one Workingpass, yet obtained the output of a multiple pass machine.

According to one suggestion, this problem was solved in that the lengthof the working pass was considerably extended by using, instead of jaws,so-called roll pass rings, the circumference of which are finished asworking passes.

Reference is made to the patent application filed by the instantapplicant jointly with others on June 6, 1966, Ser. No. 555,420, nowPat. No. 3,503,241, issued on Mar. 31, 1970.

The roll pass rings mentioned are composed of highalloyed material and,in their nature as tools, present a cost factor that needs to be keptwithin a reasonable range, its life span being of decisive importance inthat respect. The life span, save for the wear and tear of the passes,is based mainly on the type of locking connection between the roll passring or rings with the driving shaft.

The use of roll pass rings for cold rolling machines of the step-backtype is old, and the most persuasive factor for its use has been theweight reduction and saving of material achieved therewith. These rollpass rings generally were originally connected to the shaft by means ofkeys or wedges and slots or grooves, respectively, for the purpose ofachieving the calibration relative to the driving gears, andadditionally by a press fit.

Increasing output demands, however, have rendered the press fitinsufficient, and therefore, while retaining the key and groovearrangement the press fit was replaced by a shrink fit. To prolong atthe same time the life span of the pass, material of higher quality waschosen. A desirable consequence would have been to be able to refinishthe pass after a period of wear and, finally, to replace the roll passring by a new ring, performing the removal of the roll pass ring in sucha manner that the shaft remained undamaged.

Though it was known and hence possible to heat the p CC ring to asufficiently high temperature heat in order to remove it from its shrinkfit seat, either by induction heat or by other heating means,difficulties were encountered in loosening the adhesion between the keyand groove; that adhesion was found to be so intensive, having beengenerated by the working and by the shrinking operations, that the rollpass ring needed to be splintered off.

It is therefore among the principal objects of the invention to providea cold rolling mill of the step-back type that avoids the disadvantagesof the prior art.

It is another object of the invention to provide such a rolling mill inwhich the roll pass ring may be removed off the shaft withoutdifiiculty.

It is a further object of the invention to provide such a cold rollingmill in which the roll pass ring though removable without difficultystill oifers a reliable locking connection for the positive transfer ofthe torque moment.

It is still another object of the invention to provide for a heatreleasable locking connection of the aforesaid type between the rollpass ring and the shaft, capable of positively transferring a largetorque moment as found in modern cold rolling mills.

It is still a further object of the invention to provide for a high heatreleasable intensive bonding between the roll pass ring and its carriershaft sutficient for the slip-free carrying out of a high speedstep-back rolling operation.

Further objects and advantages of the invention will be set forth inpart in the following specification and in part will be obvioustherefrom without being specifically referred to, the same beingrealized and attained as pointed out in the claim hereof.

Due to the fact that modern cold rolling mills of this type generallyhave but a single drive for the upper and lower roll shafts, it is nolonger necessary to adjust the roll ring to the driving gear, as one ofthe two drive racks may be adjusted in such a mannerthe maximum distancebeing the pitch of the gearthat the upper and lower roll pass ringscoincide in relation to the pass.

The instant solution of the problem, as a result of thoroughinvestigations and observations, broadly comprises that the roll passring by correspondingly intensively shrinking is rigidly secured to theshaft without any key or groove, in such a manner that the shrink fitseat meets the requirements of modern high-speed machines. Theconnection is heat releasable, however, by the application of high heat,the ring being removable off the shaft for instance, by inductionheating to a sufiiciently high temperature followed by pulling olf,without ditficulty and without any damage to the shaft.

The shrinking of the roll pass ring onto the shaft without either key orgroove in accordance with the instant inevntion, renders it possible toprovide a single rolling mill of the step-back type that offers theadvantages not only of having an extended length of the working pass inconnection with mass balancing, and a large output, but also ofpreserving the working pass by exchanging the roll pass ring Withoutdamage to the shaft during the ring replacing procedure, resulting inconsiderable savings in tool costs.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description, taken inconnection with the accompanying drawings, in which:

FIG. 1 is a schematic sectional view of a rolling mill of the step-backtype including a frame, balancing means and a drive motor; and

FIG. 2 is a sectional view of a carrier shaft with a roll pass ringmounted thereon.

The construction according to FIG. 1 shows a cold rolling millarrangement with mass balancing means 1, a drive motor 2, areciprocating frame 3, and a roll pass ring 4 that is mounted on acarrier shaft 7 (FIG. 2). A

rack rotates the roll pass rings but has, for the sake of simplicity andclarity of the drawing, not been shown. As shown in FIGS. 1 and 2, theroll pass ring 4 is mounted and locked on the carrier shaft 7 forpositive rotation, by means of a shrink fit. Locking is accompishedwithout any key and groove connection between shaft and ring.

The carrier shaft 7 has a radially extending flange 8 that has near itscircumference in an axial direction a prismatic axial groove 9. The rollpass ring 4, on the other hand, has on its opposite faces correspondinggrooves 10, which, however, extend radially. A prismatic element 13 isinserted into the adjoining grooves 9 and 10 of the flange 8 and theroll pass ring 4, respectively, to fix the roll pass ring 4 peripherallyrelative to the carrier shaft 7. The element 13 is secured from fallingoff by means of a ring 14.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

Having thus described the invention, what I claim as new and desire tobe secured by Letters Patent, is as follows:

1. A cold rolling mill of the step-back type comprising a rotatableshaft and a single exchangeable roll pass ring mounted on said shaft,and high temperature heat releasable locking means operable for securingsaid ring to said shaft consisting of a shrink fit frictional engagementbetween said ring and shaft thereby bonding said ring on said shaftsufficiently intensively for the slip-free carrying out of high-speedstep-back rolling, said shaft including a radially extending flange, andregistering means between said flange and said roll pass ring operablefor fixing said roll pass ring peripherally relative to said shaft, saidregistering means including an axial groove defined in said flange and aradial groove defined in said roll pass ring, said grooves beingpositioned adjacent and in registry with each other, a prismatic elementpositioned in said adjacent grooves forming a connection therebetween,and a ring surrounding said shaft engaging said prismatic elementthereby restraining its removal off its position.

References Cited UNITED STATES PATENTS 1,732,043 10/1929 Fox 29-1251,938,995 12/1933 Beynon 29447X 2,192,808 3/1940 Van Der Bungelaan72-214 2,537,356 1/1951 Larsson 722l4 2,703,999 3/1955 Gille 7252142,787,956 4/ 1957 Kirby et a1. 29-447 3,030,835 4/1962 Krause 722143,309,010 3/1967 Zeunert et a1. 72238 MILTON S. MEHR, Primary ExaminerUS. Cl. X.R.

